Today’s case is an 11 year old male neutered Labrador Retriever. 1 week of progressive weakness and difficulty using the left pelvic limb. Take a look at the images and post your comments!

11 year old male neutered German Shepherd with 5 days of lethargy and 1 day of vomiting.

On abdominal radiographs, there is a large mid abdominal mass which is displacing small intestine to the periphery. The pylorus of the stomach is displaced slightly dorsally, and the fundus is caudally displaced on the v/d projection. The proximal extremity of the spleen is not visible. Differential diagnoses include enlarged spleen, pedunculated liver mass, mesenteric lymphadenopathy, or less likely a retained testicle. The mass may be neoplastic, splenic torsion, granuloma, or hematoma. Diagnosis: splenic torsion.

Adult Oldenburg/QH cross with lethargy and weight loss.

On lateral projections of the thorax, there is a severe, diffuse nodular broncho-interstitial pattern affecting all lung lobes. The nodules appear to be airway-associated. The cardiovascular structures appear normal. Differentials include inflammatory (eosinophilic bronchopneumanopathy, pulmonary nodular fibrosis, sarcoidosis, corynebacterium, hematogenous pneumonia), or metastatic neoplasia. Diagnosis: lymphoplasmacytic peribronchial inflammation with fibrosis. = pulmonary nodular fibrosis. This is an emerging disease that may be associated with equine herpes virus type 5.

Wong DM, Belgrave RL, Williams KJ, et al. Multinodular pulmonary fibrosis in five horses. Journal of the American Veterinary Medical Association 2008;232:898-905.

4 year old mustang who stopped eating 4 days ago with mild colic.

Abdominal radiographs show a collection of radiopaque material in the cranioventral abdomen. This appears to be sand within the large colon. There are multiple gas-fluid interfaces in the dorsal abdomen. There is also mottled gas and soft tissue opacity dorsal to the large colon that is likely enlarged stomach. The mottling is suggestive of emphysematous gas, possibly in the gastric wall. Diagnosis: gastric impaction.

1 year old female spayed domestic short hair cat who is smaller than littermates.

A poorly-positioned whole body, lateral radiograph is available for review. The patient was fractious. There are multiple open physes with poor mineralization of the epiphyses of the long bones. The vertebral endplates are shortened and malformed. The liver is enlarged and rounded. These changes are indicative of a congenital, develompental or metabolic disease resulting in underdevelopment of the skeleton and epiphyseal dysplasia, with possible involvement of the abdominal organs. Differentials include mucopolysaccharoidosis, congenital hypothyroidism, pituitary dwarfism. Diagnosis: congenital hypothyroidism.

8 year old dog with difficulty breathing, presented for possible lung lobe torsion.

On thoracic radiographs, there is an interstitial to alveolar pattern in the left cranial lung lobe. There are faint air bronchograms visible with a lobar sign. There are several soft tissue opacity nodules in the right caudal lung lobe. Differential diagnoses include infarction, hemorrhage (hemangiosarcoma), inhaled foreign body, neoplasia. Recommend CT for further evaluation. Diagnosis: metastatic hemangiosarcoma with hemorrhage.

Today’s case is a 3 month old Maltese puppy with difficulty defecating. Post your interpretations in the comments section! Answers will be available on Monday.

Today’s case is a male Goose of unknown age and breed presented with weight loss and open mouth breathing. All the exotic and non-domestic specialists, post your comments! Answers will be available on Monday.

Today’s case is a 5 month old male Mastiff who is reluctant to walk. Enjoy the case, post your comments and interpretations.

This week at known case conference we had a collection of interesting thoracic cases. When evaluating masses, try to determine where they are originating and what surrounding structures they affect. There are some clues below that help with localization in each case.

4 year old German Shepherd with respiratory difficulty

On thoracic radiographs, the cranial mediastinum is widened with increased soft tissue density. There is elevation of the trachea and increased density at the hilus with depression of the mainstem bronchi. There are several fissue lines indicating mild pleural effusion. Differential diagnoses for lymphadenopathy and pleural effusion include lymphoma, metastatic neoplasia, fungal pneumonia (aspergillosis in German Shepherds). Recommendations: ventrodorsal projection, abdominal ultrasound. Diagnosis: Aspergillosis. Comment: Check abdomen for fungal disease in spleen, kidneys. Fungal diseases that can cause pleural effusion include aspergillosis, coccidiomycosis.

4 year old Lab cross with coughing and dysphagia

On thoracic radiographs, there is an alveolar pattern in the left cranial lung lobes with air bronchograms and a mediastinal shift to the left. There is also increased opacity dorsal to the trachea which is displacing it ventrally and causing tracheal narrowing. Radiographic diagnosis: esophageal or mediastinal mass causing tracheal compession with possible esophageal dysfunction and secondary aspiration pneumonia. Differential diagnoses include esophageal neoplasia, fungal esophagitis (pythiosis, cryptococcus), mediastinal mass (foreign body, hemorrhage), pulmonary mass. Differentials for the pulmonary pattern include atalectasis +/- additional pneumonia, and bronchial compression by the mass. Recommendation: Esophagram. On the esophagram, the esophageal lumen is normal in size with dorsal deviation over the heart base, indicating an extraluminal mass. Diagnosis: mediastinal Nocardia granuloma.

6 year old lab cross with rales and paroxysmal coughing

There is a diffuse interstitial to alveolar pulmonary pattern with some air bromchograms ventrally. The pattern is most severe in the caudodorsal lungs. The right heart is mildy enlarged as are the pulmonary arteries. Differentials include heartworm disease, non-cardiogenic pulmonary edema, hemorrhage, embolic pneumonia, pulmonary embolism. Diagnosis: Heartworm disease. Marked improvement on anti-inflammatory therapy.

At this week’s KCC, we had a great variety of cases. The first case was tricky to interpret; the radiographic findings did not fit well with the history and clinical signs. This should always raise your index of suspicion that there is something else going on. Here are the case summaries, no images this time.

8 year old FS Australian Shepherd with acute right forelimb lameness.

Radiographs of the right radius and ulna are presented. There is a thin-walled lucency in the distal lateral radius. There is no evidence of cortical disruption or periosteal reaction. The zone of transition is sharp. Differential diagnoses include a bone cyst, and neoplasia (osteosarcoma, round cell neoplasia). Considering the history, the dog is older which is less characteristic of a bone cyst. In addition, it does not explain the acute lameness. The metaphyseal location of the lesion could also fit with a primary bone tumor. Because of the thin cortex, a pathological fracture is possible and follow-up radiographs are be warranted. Possible next steps include thoracic radiographs and bone aspirate or biopsy. Diagnosis: fibrosarcoma.

6 year old male neutered German Shepherd with an abdominal mass.

On abdominal radiographs, there is a large soft tissue mass in the right abdomen or retroperitoneal space. It is causing a mass effect with peripheral displacement of the small intestine. The left kidney is visible and caudally displaced. The right kidney is not clearly visible, but appears to be displaced by the mass to the ventral abdomen on the lateral projection. The spleen is visible and appears normal. Differentials include right renal hydronephrosis, neoplasia, other organ neoplasia (mesenteric, splenic, pancreatic), abscess, hematoma, granuloma. An abdominal ultrasound or EU was recommended. An excretory urogram was performed with two available time points. The left kidney is normal with a normal nephrogram and pyelogram. The right kidney enhances poorly, and the mass apears to be continuous with the pelvis. The mass does not enhance, but there is an irregular rim of contrast enhancement at the right renal pelvis which appears to be dilated renal diverticuli. A segment of normal ureter travels toward the bladder. Revised differentials include a retroperitoneal mass causing right ureteral obstruction (cyst of renal or ureteral origin, neoplasia, infectious, inflammatory). Diagnosis: cystadenocarcinoma and nodular dermatofibrosis (skin lesions not mentioned in history). German Shepherds are predisposed to this condition, which is caused by a mutation in the canine BHD gene. Multifocal renal tumors, uterine lyomyomas, and skin nodules comprised of dense collagen are all part of the syndrome.

Moe, L. and B. Lium (1997). “Computed tomography of hereditary multifocal renal cystadenocarcinomas in German shepherd dogs.” Veterinary Radiology & Ultrasound 38(5): 335-43.
Lingaas, F., K. E. Comstock, E. F. Kirkness, A. Sorensen, T. Aarskaug, C. Hitte, M. L. Nickerson, L. Moe, L. S. Schmidt, R. Thomas, M. Breen, F. Galibert, B. Zbar and E. A. Ostrander (2003). “A mutation in the canine BHD gene is associated with hereditary multifocal renal cystadenocarcinoma and nodular dermatofibrosis in the German Shepherd dog.” Hum Mol Genet 12(23): 3043-53.

4 year old Quarter Horse colt who caught limb in fence. 4/5 lame RH.

At the pastern, there is synovial proliferation and effusion in the digital sheath with soft tissue thickening. The margin of the tendon sheath is disrupted distally with fluid collecting in the subcutaneous tissues. The origin of the medial collateral ligament has a central anechoic disruption seen in short and long axis. Diagnosis: tenosynovitis with ruptured tendon sheath, and desmitis of the medial collateral ligament. Recommendation is to perform ultrasound guided centesis. Notes: To tell the difference between the transverse and longitudinal views of the collateral ligament, look at the contour of P1. The transverse is concave and parallel to the image, while the longitudinal image has an angled bone surface.

4 year old domestic short hair cat with several days of fever, anorexia, sneezing and coughing.

On thoracic radiographs, there is a diffuse bronchointerstitial pattern. The lungs are mildly hyperinflated. There is increased opacity in the area of the esophagus on the lateral projection. Differentials for this non-specific radiographic pattern include infectious lower airway disease such as fungal (cryptococcus, toxoplasmosis, histoplasmosis, blastomycosis), heartworm, bacterial, parasitic or viral. Diagnosis: Aelurostrongylus abstrusus. The adult worms lay their eggs in the bronchioles and alveolar ducts. Many cats are asymptomatic with this disease.

For those of you interested in marine mammals, here’s a link to  www.marinemammalradiology.com. The site was created by the Marine Mammal Center, the Shedd Aquarium, and the Alaska Sealife Center. There are normal radiographs, a CT and an MRI scan of the California Sea Lion available to look at, as well as a few example cases. It’s a great resource!

Aquatic animal medicine is an extremely exciting and fast expanding area of veterinary medicine. The goal of www.marinemammalradiology.com is to provide a reference for the normal radiographic, computed tomographic and magnetic resonance anatomy of marine mammal species commonly found in captive and rehabilitation settings. Furthermore we hope to disseminate information on the radiologic diagnosis of disease as such cases become available for publication. The website is a ‘work in progress’ with many institutes contributing data. In addition, institutes contribute to the website by offering advice on the diagnostic imaging information needed by the marine mammal community. We hope that you will enjoy the site!

This week I’ll feature another great case from the CT/MRI society. This one is an equine MRI case contributed by Dr. Alexia McKnight. Enjoy!

Well the new quarter is in session so we are back at Known Case Conference to challenge the residents with reading radiographs.The case moderator knows the answer but the residents have to narrow it down to their best list of differential diagnoses.

We hold KCC rounds after work in a barn on the west side of town. Not just any barn, it’s fully equipped with light boxes, a projector and screen (for digital cases) and wireless internet. And beverages and snacks of course. This week I rode my bike out to the barn on a windy day. A large unidentified  insect blew into my forehead and stung me, so I spent most of the session lamenting how much my head hurt! Anyway here are a few of the case summaries for you.

Case 1 – 8 year old male neutered dog with an acute abdomen

The abdominal radiographs had poor detail, and the contour of the abdominal wall was distended. The spleen was enlarged and curved in a “reverse C” shape on the lateral projection. The proximal extremity of the spleen was visible on the lateral ventral to the cecum, then the body curved caudally and the distal extremity was just caudal to the liver. The small intestine was displaced by this enlarged spleen. Differential diagnoses included splenic torsion, and inflammatory or diffuse infiltrative disease. Diagnosis: Splenic torsion. These have a very characteristic position and shape if there isn’t too much effusion obscuring them. There is no contour change such as with a mass. Check the v/d projection to see that the proximal extremity of the spleen is not visible in its normal position.

Case 2 – 1 year old male neutered German Shorthair Pointer with lethargy.

These thoracic radiographs had an asymmetric interstitial pattern that was most pronounced in the left cranial lung lobe. There was interstitial pattern dorsally as well, and the distribution was patchy. The heart and vessels were normal, as was the pleural space. Differentials included hemorrhage, atypical pneumonia or inflammatory disease, or non-cardiogenic edema. Diagnosis: hemorrhage from rodenticide toxicity. Hemorrhage is often asymmetrically distributed. Dogs with rodenticide toxicity may also have a widened medastinum from accumulation of blood.

Case 3 – 2 year old Australian Shepherd cross with left hind limb lameness.

A lateral radiograph of the spine and pelvis showed an aggressive bone lesion of L5 with permeative osteolysis and marked ventral new bone production. There was also faint periosteal reaction on one of the femurs. On the v/d, the left femoral neck was lytic with an apple core appearance. The left ileal wing was sclerotic with increased periosteal new bone. Differentials for aggressive polyostotic bone lesions: fungal osteomyelitis, bacterial osteomyelitis, neoplasia. The latter two are much less likely than fungal disease. Diagnosis: Coccidiodomycosis. Here’s a different case with coccidiodomycosis of the pelvis.

Just a quick note to say that links to cases may be unavailable over the next 24 hours while the server is assigned a new IP address. I’ll be updating the old links as well, but please send me an email if you have trouble accessing cases Wednesday afternoon.

The freshman class has been asking me all sorts of great questions pertaining to abdominal radiology. I thought I would share some of the questions and answers with you.

What are the radiographic signs for free peritoneal gas?

There are a few different signs to look for when you suspect free peritoneal gas. Serosal surfaces, especially ones that you would not normally see (liver lobes) become visible from the high contrast between gas and soft tissue. You will also see gas that is not contained within the gastrointestinal tract. These gas bubbles often have odd, angular shapes. Gas also tends to rise to the highest point in the abdomen, which is under the diaphragm in both projections. Look for the diaphragm to be outlined by gas on both sides. It is usually highlighted by gas (lungs) on the cranial side, but the caudal side should have stomach wall or liver adjacent to it. When outlined on both sides by gas, the diaphragm will appear as a very thin, sharp, soft tissue line.

Signs to look for:

*increased peritoneal detail

*angular gas bubbles not contained in the GI tract

*diaphragm outlined by gas on both sides

Is there any benefit to fasting an animal prior to radiographing in order to see the GI tract better?

Yes, fasting the animal and taking it outside will ensure that the stomach and colon are empty. The stomach can cause a mass effect in the cranial abdomen when it is full. Radiopaque material in the colon can also obscure portions of the abdomen. An empty GI tract as well as urinary bladder makes for a much better study.

How can I identify the different parts of the diaphragm on a radiograph?

Generally, when the animal is in lateral recumbency, the weight of the abdominal organs push on the dependent crus. If the animal is in left lateral, that would be the left crus. So you will usually see the left crus projected in front of the right in left lateral recumbency. The opposite is true for right lateral recumbency. But there is a lot of variation in diaphragm conformation between animals, and where you center the x-ray beam, so you won’t see these changes every time. Just remember the fundus sits under the left crus, and the caudal vena cava enters the right crus for landmarks.

The cupula is sometimes visible on a lateral radiograph, but is seen better on the v/d as the most cranial part of the diaphragm centered on midline. The two crura can look like “Mickey Mouse” ears.

January’s gathering of wildlife and zoo veterinarians had a great collection of interesting cases. Here are some of the highlights.

Mature Flamingo, found unable to rise

This flamingo did not have any history of disease and was up to date on vaccinations. His initial blood work was fairly normal. Radiographs showed increased opacity of the soft tissues including great vessels in the thorax, and mineralization of the kidneys. Later blood work showed increased renal values fitting with the radiographic signs of renal mineralization. Differentials could include primary or secondary hyperparathyroidism or gout. Post mortem examination confirmed crystals within the renal parenchyma and mineralization of vessels. Final results are pending.

Flying Fox with mass on mandible

Aspirates of this soft tissue mass were not conclusive. Dental radiographs with very nice detail showed a lucency at the apex of the left canine tooth in the mandible, indicating a periapical abscess.

Mature Sea Lion with open mouth

The Sea Lion had bilateral mandibular fractures located in the ramus of the mandibles. The temporomandibular joints were not directly involved. The fractures had some remodeling of the edges and were relatively well aligned. They were most likely a week or two old, and the massive masticatory muscles had kept the fractures from greater displacement. The animal was able to close its mouth and to eat. He did very well with supportive care. The group speculated on the type of trauma that would induce this type of injury, possibly an impact from the ventral or caudoventral area.

Harbor Seal pup with fractured radius

This pup had a fractured radius with several fragments. Radiographs over a period of 3 months showed progressive healing of the more proximal portion of the fracture, with incorporation of a fragment into the distal callus. This subsequently formed a mineral opacity sequestrum surrounded by a symmetric involucrum (radiolucent line around the sequestrum). The sequestrum dissolved completely over this period without surgical debridement.

River Otter found in parking lot

Thoracic radiographs showed a generalized cardiomegaly. The thorax of the otter was shaped like a feline thorax, and the heart appeared to be approximately twice normal size. The lungs and remainder of the thorax were normal. An unknown protozoal parasite was found in the muscles and myocardium. Final speciation was pending.

Are you a student or intern deciding what specialty to choose? This article from the CMAJ explains how to rate your goo tolerance on the GROSSS scale.

Radiology

Practically goo-free. You get to sit around in a sterile office all day looking at pictures of goo, but you never have to touch it.

The keynote speakers at the ACVR meeting all had very interesting perspectives on the future of imaging. Here is a short summary of the speakers with some links to further information.

Michael Garwood from the University of Minnesota Presented “Beyond anatomy: Imaging molecules, function and disease using advanced magnetic resonance technologies”. Some of his areas of interest include using MR spectroscopy to diagnose breast cancer and monitor response to treatment, and functional MR of the brain.

Fleming Forsberg from the Thomas Jefferson University Hospital in Philadelphia gave a very entertaining talk entitled “Animal models for ultrasound contrast imaging research”, and touched on many techniques including recent advances in contrast harmonic imaging.

Chick Weisse from the University of Pennsylvania spoke about “IR or the OR”, and advances in veterinary interventional radiology. This field has many applications such as treatment of portosystemic shunts and collapsing trachea.

Joseph Hornak from the Rochester Institute of Technology gave a very nice talk on various MR topics. He has also written an online book entitled “The basics of MRI“. He spoke about advances in coil design and image acquisition that would significantly shorten the time needed to complete a study.